Wafer-level manufacture of camera modules manufactured with complementary metal-oxide semiconductor (CMOS) technologies has contributed to the incorporation of camera modules in high-volume consumer products such as mobile devices and motor vehicles.
FIG. 1 shows a wafer-level lens 100 incorporated into a camera module 192 of a mobile device 190. FIG. 2 is a cross-sectional view of a prior-art lens assembly 200 that is an example of wafer-level lens 100. Lens assembly 200 includes a lower substrate 210 and an upper substrate 240 separated by a spacer ring 230. Upper substrate 240 includes an upper lens 242 that is axially aligned to a lower lens 212 on lower substrate 210.
Lower substrate 210 and an upper substrate 240 include alignment structures 251 and 252 respectively. Lower lens 212 and upper lens 242 include alignment structures 253 and 254 respectively. Alignment structures 251-254 are used to ensure axial alignment of lenses 212 and 242 during fabrication of lens assembly 200. A drawback of lens assembly 200 is that incorporating alignment structures 251-254 into substrates 210, 240 and lenses 212, 242 adds manufacturing costs and complexity.